Molecular basis of alpha-thalassemia in Iran

Alpha-thalassemia [alpha-thal] is probably the most prevalent monogenic condition in the world. Deletions are the most common types of mutations in alpha-thal, followed by point mutations and small insertion/deletion. In the context of national screening program for prevention of thalassemia and hemoglobinopathies in Iran, alpha-thal carriers have come to more attention. Therefore, the frequency and distribution of alpha-globin mutations in various regions of the country have been studied in recent years. A comprehensive search was performed in PubMed, Scopus, and national databases for finding reports on mutation detection in alpha-thal carriers and HbH disease with Iranian origin. The mutation data of 10849 alpha-thal carriers showed that -alpha[3.7] and alpha[-5NT] were the most common deletional and nondeletional mutations, respectively. In HbH disease cases, the -alpha[3.7]/-[-MED] was the most prevalent genotype. Overall, 42 different mutations have been identified in alpha-globin cluster reflecting the high heterogeneity of the mutations in Iranian populations

Promoter hypermethylation of estrogen receptor alpha gene is correlated to estrogen receptor negativity in Iranian patients with sporadic breast cancer

Breast Cancer is the most common cancer in Iranian women. Breast tumors are classified based on the estrogen receptor alpha [ER alpha] expression status into ER negative and ER positive tumors. ER negative tumors tend to have worse prognosis and less likely to respond to endocrine therapy. Aberrant methylation of gene promoter is one of the mechanisms for gene silencing in breast tumors. Because of its reversible nature, promoter methylation is a good target for new therapeutic strategies. We aimed to evaluate the frequency of this epigenetic event in ER alpha gene and its association to clinicopathological features in Iranian breast cancer patients. In this case control study the patient series consisted of 100 sporadic primary breast cancer cases [51 ER negative and 49 ER positive tumors]. None of the participants had chemo or radiotherapy before surgery. In breast tumors ER alpha promoter methylation were assessed with methylation specific polymerase chain reaction [MSP]. Data was collected on clinicopathological features of the patients. Correlation between ER alpha methylation and clinicopathological characteristics of the patients was investigated by Pearson Chi-Square and Fisher's exact test. ER alpha methylation was detected in 98% of ER negative and 65% of ER positive breast tumors. A strong correlation was found between ER alpha methylation and ER negativity in tumors [p<0.0001]. Also, ER alpha methylation has associated to progesterone receptor negativity [p<0.008] and double receptor negative status [p<0.0001] in breast tumors. ER alpha methylation occurs with high frequency in the breast tumors of Iranian breast cancer patients and may play a considerable role in pathogenesis of ER alpha negative tumors as a poor prognosis and more aggressive category. The reversible nature of DNA methylation may provide new therapeutic possibilities in ER negative breast tumors

First report on the Co-inheritance of beta-globin IVS-I-5 [G-C] thalassemia with delta globin CD12 [Asn-Lys [AAT-AAA]] hba2- NYU in Iran

Background: co-inheritance of beta- and delta-globin mutations in Iran is not uncommon. This situation may interfere with correct diagnosis and genetic counseling of alpha- and beta-thalassemia in screening programs. Here we report the co-inheritance of beta- and delta-globin gene mutations in an individual with microcytosis, hypochromia and a normal hemoglobin A2 [HbA2] level

Methods: genomic DNA extraction, amplication refractory mutation system [ARMS] polymerase chain reaction and direct DNA sequencing of delta- and beta-globin genes were exploited for detection of the mutations in these two genes in an individual with low hematological indices and normal HbA2

Results: ARMS-PCR technique revealed the beta+ IVSI-5 [G to C] mutation and direct DNA sequencing of the delta-globin gene detected a previously reported delta codon 12 [AATàAAA] HbA2-NYU. This study reports HbA2-NYU in association with the beta IVSI-5 [G to C] mutation in Iran

Discussion: this report emphasizes that normal HbA2 expression in a beta-goblin carrier is due to mutation in the delta-globin gene and may cause misdiagnosis of thalassemia

Co-inheritance of hemoglobin D and beta-thalassemia traits in three Iranian families: clinical relevance

Here we report the result of three cases referred to our lab that had a combination of beta-thalassemia and hemoglobin D [Hb D] traits. These individuals had no symptoms of profound anemia and hematological indices were similar to that of a beta-thalassemia heterozygote. In all three cases, the Hb D level was elevated and no HbA was detected electrophoretically. The electrophoresis pattern suggested that all cases were homozygotes for Hb D. PCR followed by digestion with EcoRI and sequencing of the beta-globin gene confirmed the presence of Cd 121 GAA>CAA in the heterozygous form with another beta-globin mutation. In all cases, the mutations in the beta-globin gene were detected by ARMS PCR technique and they were either IVSII-I or IVSI-5. Hematological studies of the family members showed that thalassemia which caused the mutations and Hb D were in the Trans position

Transient expression assay of [A]gamma-588 [A/G] mutations in the k562 cell line

In the previous study, we have shown that the presence of A allele at position -588 in [A]gamma -globin gene was highly frequent and closely associated with fetal hemoglobin elevation among beta-thalassemia intermedia patients. Therefore, we decided to investigate whether this allele [A allele at -588] could result in an increase in [A]gamma-globin gene expression to ameliorate the severity of the disease in thalassemia patients. Three constructs containing ji locus control region, [A]gamma -globin and beta-globin genes were designed and employed in the transient expression assay. The difference among constructs was in the promoter region of, [A]gamma -globin gene [A and G alleles at -588]. A construct with T to C base substitution at -175 of, [A]gamma -globin, created by site-directed mutagenesis, was selected as positive control. The K562 cell line was transfected with the above constructs. Subsequently, the expression of, [A]gamma -globin gene was determined by quantitative real-time reverse transcription-PCR. There was not a significant increase in the expression of, [A]gamma -globin gene in the construct containing A allele comparing the one with G allele at -588. -588 [A>G] mutation does not play a major role in regulation of, [A]gamma -globin gene, suggesting that other factors may be involved

Association between ABCB1-T1236C polymorphism and drug-resistant epilepsy in Iranian female patients

One third of epileptic patients are resistant to several anti-epileptic drugs [AED]. P-glycoprotein [P-gp] is an efflux transporter encoded by ATP-binding cassette subfamily B member 1 [ABCB1] gene that excludes drugs from the cells and plays a significant role in AEDs resistance. Over-expression of P-gp could be a result of polymorphisms in ABCB1 gene. We studied the association of T129C and T1236C single-nucleotide polymorphisms [SNP] of ABCB1 gene with drug-resistant epilepsy in Iranian epileptics. DNA samples were obtained from 200 healthy controls and 332 epileptic patients, of whom 200 were drug responsive and 132 drug resistant. The frequencies of the genotypes of the two SNP were determined by polymerase chain reaction followed by restriction fragment length polymorphism. No significant association was found between T129C and T1236C genotypes and drug-resistant epilepsy neither in adults nor in children. However, the risk of drug resistance was higher in female patients with 1236CC [P = 0.02] or CT [P = 0.008] genotype than in those with TT genotype. The risk of drug resistance was also higher in patients with symptomatic epilepsies with 1236CC [P = 0.02] or CT [P = 0.004] genotype than in those with TT genotype. The risk of drug resistance was lower in patients with idiopathic epilepsies with 129TT genotype [P = 0.001] than in those with CT genotype. Our results indicate that T1236C polymorphism is associated with drug resistance in Iranian female epileptic patients. Replication studies with large sample sizes are needed to confirm our results

[Detection of unknown deletions in alpha globin genes in alpha thalassemia carriers using real-time PCR]

Alpha-thalassemia is one of the most prevalent hemoglobin disorders in the world and it is a common hereditary condition caused by deletion of one or more alpha-globin genes. Common alpha-thalassemia deletions like 3.7 kb, 4.2 kb, 20.5 kb and Med can be detected by Multiplex PCR. There are, however, some unknown deletions that can not be detected by the mentioned method or even by direct DNA sequencing. In the present study, Real-time PCR was used to determine the presence or absence of unknown deletions. Real-time PCR was performed using intercalating dye SYBR Green I and alpha1, alpha2 and CLCN7 genes were amplified. Data analysis was conducted using comparative threshold method [delta delta CT] for determination of Gene dosage of alpha1-globin and alpha2-globin genes. The results showed the ratio of 0.90 +/- 0.16 for normal individuals and the ratio of 0.32 +/- 0.15 for carrier samples with deletions. In addition, Melting curve analysis confirmed the specific amplification of target genes. The Real-time PCR assay is simple, rapid, and reliable. It can be applied for direct determination of unknown deletions in Alpha-thalassemia carriers